This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Patent Application No. 2001-310754 filed on Oct. 5, 2001, the entire content of which is incorporated herein by reference.
1. Field of the Invention
This invention relates to a light scanner used to write information onto a disk and read information on a disk using a light beam and in particular to a light scanner having an optical system unit including a half mirror.
2. Description of the Related Art
This kind of light scanner applies a light beam to a rotating disk, thereby reading or writing information from or onto the disk, wherein an optical system unit for applying a light beam can be moved in a direction along the radius direction of the disk and optical parts such as a half mirror are built in the optical system unit.
FIG. 5 is a partial plan view of an optical system unit adopted for a light scanner in a related art, FIG. 6 is a sectional view taken on line VIxe2x80x94VI of FIG. 5, and FIG. 7 is a perspective view of a mirror fixture. A light scanner in a related art will be discussed with reference to FIGS. 5 to 7.
In the light scanner, an optical system unit 1 made of a synthetic resin molded substance is formed with through holes 2 and 3 for forming an optical path, and a half mirror 4 facing the through holes 2 and 3 is attached to the optical system unit 1. Specifically, the optical system unit 1 is formed with a recess space 5, the left and right end parts of the rectangular half mirror 4 are placed on an inclined mirror attachment reference face 6 formed stepwise in the inside of the recess space 5, and the half mirror 4 is pressed against and fixed to the mirror attachment reference face 6 by the action of a mirror fixture 7.
As shown in FIG. 7, the mirror fixture 7 is made of a metal steel and has a pair of left and right arm-like press parts 71 and 71 and an attachment part 72 and the attachment part 72 comprises a pair of left and right protrusion piece parts 73 and 73 and retention claws 74 and 74 cut and raised. The attachment part 72 is inserted into a groove-shaped recess part 8 formed on the rear of the recess space 5 of the optical system unit 1, the front end margins of the left and right protrusion piece parts 73 and 73 of the attachment part 72 are abutted against a front wall 81 of the groove-shaped recess part 8, edge-like end margins 74a and 74a of the retention claws 74 and 74 are retained on a rear wall 82 of the groove-shaped recess part 8 in a press state, and the left and right press parts 71 and 71 overlap the left and right end parts of the half mirror 4 for pressing and fixing the half mirror 4 against and to the mirror attachment reference face 6.
On the other hand, JP-A-3-174108 describes use of a plate spring and an adhesive to fix a half mirror to an optical system main body (corresponding to the above-described optical system unit) in an optical information record and playback apparatus, fitting a positioning hole of the plate spring into a resin boss part placed in the optical system main body to fix the plate spring to the optical system main body, etc.
JP-A-2000-235158 describes a configuration for attaching a plate spring to a mirror holder screwed into an optical box of a light scanner and holding a half mirror on the mirror holder by the plate spring.
Further, JP-A-2-135922U describes a configuration for using a plate spring to position a half mirror placed in an optical parts holder of an optical pickup.
In the light scanner in the related art described with reference to FIGS. 5 to 7, the attachment part 72 of the mirror fixture 7 is inserted into the narrow groove-shaped recess part 8 and the end margins 74a of the retention claws 74 cut and raised in the attachment part 72 are retained on the rear wall 82 of the groove-shaped recess part 8 in a press state. Thus, the retention claws 74 are retained on the rear wall 82 of the groove-shaped recess part 8, whereby the removal prevention effect of the mirror fixture 7 is exerted. However, after the mirror fixture 7 is once attached to the optical system unit 1, it is difficult to remove the mirror fixture 7 and if the mirror fixture 7 is forcibly pulled out for removal, the end margins 74a of the retention claws 74 scratch or cut away the rear wall 82 of the groove-shaped recess part 8. Therefore, even if the attachment state becomes defective in the attachment process of the mirror fixture 7 to the optical system unit 1, it is difficult to remove the mirror fixture 7 from the optical system unit 1 and again attach the mirror fixture 7 thereto, and it is made impossible to again use the optical system unit 1 from which the mirror fixture 7 is removed because the optical system unit 1 is scratched, etc.; this is a problem.
The arts described above in JP-A-3-174108, JP-A-2000-235158, JP-A-2-135922U, etc., do not fix the mirror fixture to the optical system unit by retaining the edge-like end margins of the retention claws on the wall of the optical system unit.
It is therefore an object of the invention to provide a light scanner wherein although a mirror fixture can be attached to an optical system unit by simple operation similar to that in the related art described with reference to FIGS. 5 to 7, the once attached mirror fixture can be easily removed from the optical system unit and moreover it is made possible to reuse the removed mirror fixture and reuse the optical system unit from which the mirror fixture is removed.
In a light scanner according to the invention, an attachment part of a mirror fixture comprising press parts to press and fix a half mirror against and to a mirror attachment reference face of an optical system unit is fixed to the optical system unit.
The attachment part of the mirror fixture is housed in a recess part of the optical system unit, edge-like end margins of a pair of opposed engagement piece parts of the attachment part are retained on a pair of opposed walls in the recess part in a press state, and the engagement piece parts comprise operational piece parts for elastically deforming the engagement pieces parts inward for releasing the retention state of the end margins and the walls of the recess part.
In the configuration, simply by inserting the attachment part of the mirror fixture into the recess part of the optical system unit, the edge-like end margins of the engagement piece part pair of the attachment part can be retained on the pair of opposed walls in the recess part in a press state, so that the attachment workability of the mirror fixture to the optical system unit becomes equal to that in the related art described with reference to FIGS. 5 to 7. To remove the mirror fixture from the optical system unit, the operational piece parts can be operated for inward elastically deforming the engagement piece parts engaging the walls of the recess part in a press state for releasing the retention state of the end margins of the engagement piece parts and the walls of the recess part. Thus, it is possible to take out the attachment part from the recess part and remove the mirror fixture from the optical system unit without scratching or cutting away the wall of the recess part. Thus, it is possible to reuse the removed mirror fixture and reuse the optical system unit from which the mirror fixture is removed.
In the invention, preferably the operational piece parts are projected backward from the engagement piece parts and the optical system unit is provided with an operational jig insertion recess-in part for housing the operational piece parts and being wider than the recess part. Accordingly, the operational piece parts can be operated in a state in which the tip of the operational jig such as tweezers is inserted into the recess-in part and as the operational piece parts are operated, the retention state of the end margins of the engagement piece parts and the walls of the recess part can be released. The engagement piece parts are housed in the recess part and the operational piece parts projected backward from the engagement piece parts are housed in the recess-in part, so that the engagement piece parts and the operational piece parts do not project from the optical system unit. Thus, a situation in which the operational piece part is operated by accidental operation of mischief, etc., is prevented.
In the invention, preferably the operational piece part has a plate piece part provided in one piece extending between lower end margins of the engagement piece parts and the plate piece part is formed with a split groove extending forward from the rear end of the plate piece part. Accordingly, the plate piece part is formed with the split groove, so that the elastic force of the engagement piece part is exerted not only by the elastic action of the engagement piece part itself, but also by the elastic action of the plate piece part. Thus, it becomes easy to adjust the magnitude of the elastic force when the engagement piece part is retained on the wall of the recess 9.
In the invention, preferably the plate piece part is put on a bottom wall of the recess part and is formed with an insertion hole of a mounting screw screwed into the optical system unit. Accordingly, it is made possible to attach the mirror fixture to the optical system unit more reliably with the mounting screw.
The light scanner according to the invention can be configured more specifically as follows: A light scanner wherein an attachment part of a mirror fixture comprising arm-like press parts to press and fix a half mirror against and to a mirror attachment reference face of an optical system unit is fixed to the optical system unit, wherein the attachment part of the mirror fixture is housed in a recess part of the optical system unit, wherein edge-like end margins of a pair of opposed engagement piece parts of the attachment part are retained on a pair of opposed walls in the recess part in a press state, wherein operational piece parts for elastically deforming the engagement pieces parts inward for releasing the retention state of the end margins and the walls of the recess part are extended backward from the engagement piece parts, wherein the optical system unit is provided with an operational jig insertion recess-in part for housing the operational piece parts and being wider than the recess part, wherein a plate piece part of the attachment part extending between lower end margins of the engagement piece parts is put on a bottom wall of the recess part, and wherein the plate piece part is formed with an insertion hole of a mounting screw screwed into the optical system unit and a split groove crossing the plate piece part in a back and forth direction in a rear part of the insertion hole.
The advantages of the invention will be discussed in detail in the following embodiment: